Jump-spark igniter-plug.



L. B. CHERRY.

JUMP SPARK IGNITER PLUG.

APPLICATION FILED JAN. 17, 1910.

Patented June 21, 1910.

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ments in spark ears are grn rnnc LOUIS BOND CHERRY, OF ABERDEEN, SOUTHDAKOTA, ASSIGNCR, BY DIRECT AND MESNE ASSIGNMENTS, TO THE BALLMULTI-SPARK PLUG- 00., OF ABERDEEN, SOUTH JUMP-SIP acacia.

Application filed January 17, 1910. Serial No. 538,525.

Specification of Letters .iatent.

DAKOTA, A coarona'rron or sonrn nexora.

:1 IGNITER-PLUG; I

Patented June 21, 1910.

will enable others skilled in the art to which it appertains to make anduse the same.

ThIS invention relates to certain improvelugs for internal combustionengines, and more particularly to improvements in what might be termedjump spark igniter plugs; and the objects and nature of the inventionwill be readily understood by those skilled in the art in the light ofthe following explanation of the accompanying drawings illustrating whatI now consi er my preferred embodiment from among other formations,arrangements and combinations within the spirit and scope of myinvention.

An object of the invention is to provide certain improvements in sparkplugs whereb liability of fouling and short circuiting wifl be reducedto the minimum, and an exceedingly eflicient, simple and durable devicewi 1 be produced for the urposes intended. A further object of einvention is to provide certain, simple, durable and efiicientimprovements 1n spark plugs for the purose of intensifyingand'increasing the caoric value of the spark produced.

The invention consists in certain novel features in construction, informations of parts, or in combinations and arrangements as more fullyand particularly set forth hereinafter.

Referring to the accompanying drawings:

Figure 1, 1s a side elevation of a plug, on

plosive en 'ne as will be readily understood y those s illed in the art.This shell at its outer end is exteriorly formed at 10, to receive awrench or other implement whereby the plug can '56 rotated in screwingthe same into or from the cylinder. The outer portion of the'internallongitudinal bore of the shell is enlarged and threaded thereby forminthe intermediate annular outwardly facing internal shoulder 11, fromwhich the reduced )ortion of the bore extends to the inner en of theshell.- At its inner end, the shell is preferably formed with aninternal an iular flange or bead 12, around the inner end opening of theshell. This'fiange or bead is preferably rounded or semi-cylindrical incross section and preferably is formed with a continuous smooth surfaceunbroken by points or projections throughout the circle thereof, to formand constitute a rounded continuous or annulamelec- 'trode projectinginwardly beyond the internal surface of the shell bore.

2, is the longitudinal elongated insulating plug or body composed of anysuitable insulating or non-conductin material, .such as porcelain or thelike, an formed to longitudinally and removably enter the bore of theshell and to be held thereinby the nut 3, through which the insulatingplug or body looselyextends, and which screws into the threaded outerend of the shell bore and forces the insulating plug inwardly of theshell by the engagement of the inner end of the nut with the annularshoulder shoulder 11, and surrounding'the reduced inner end portion orskirt 21 of the insulating plug and seated against the usually flared orinclined annular exterior shoulder 22, of said plug. If so desired, thispacking ring can be formed by one or more asbestos washers covered by orinclosed wlthin a rin of copper or other suitable sheet material? Theouter end of the plug adjusting and clampin nut 3, beyond the outer endof the shell, is formed with an exposed enlarged head 30, formed toreceive a wrench or other instrument whereby the nut can be rotated toscrew the nut inwardly or outwardly within the shell. The reduced innerend portion of the insulating plug forms an annular skirt 21, arrangedon 'tudinally and concentrically within the re uced portion of the boreof the shell and terminating short of the annular end electrode 12, ofthe shell, and, forming an annular fluid compression chamber within theshell around said skirt and extending from the open inner end of theshell longitudinally thereof to the packing washer 4. The insulatingplug is formed with a longitudinal bore extending through the lengththereof, and the inner end portion of this bore is enlarged to form acompressed fluid cavity or chamber 24:, open at the inner end of theplug and forming the hollow interior of the skirt 21, and terminating inthe intermediate internal annular seat or shoulder 23, within the plug.

5, is a longitudinally threaded conducting stem or rod removablyextending through the bore of the insulating plug an projecting beyondthe ends thereof, and at its inner projecting end carrying the electrode50, fixed thereto. Intermediate its length, the stem is provided withlongitudinally adjustable stop nut 51, cooperating with the internalshoulder 23 of the plug to limit the outward movement of the stem in theplug, and usually packing washer 6, of asbestos, or other suitablematerial, is

' interposed between, shoulder 23, and said diameter of the sphericalelectrode. .tspherical electrode is spaced a distance from stop nut. Thestem (and consequently the electrode 50) is held in place by the cap 7removably fitting the outer end of the insulating plu and screwing onthe rojecting end of t e stem. The end of the stem projecting beyondsaid cap is provided with a binding nut 8, by which theelectricconductor from the magneto, vibratin coil box or other suitable sourceof high requency electric current, while the return can be made throughthe shell and engine cylinder as usual or in some other suitable manner.The position of the electrode 50, with respect to the opposite electrode12, and with respect to the end of the insulating skirt can be varied byseparating the parts and changing the longitudinal position of the stopnut 51. The electrode 50, is preferably in the form of a smooth-surfaces herical metal body or ball of less diameter t an the internal diameterof the annular opposingelectrode 12, and arranged concentrically w1th1nthe same to form the annular spark gap a, within the annular electrodeand around the spherical electrode. The.spher- 1cal electrode is soarranged with respect to the annular electrode that the plane of theannular electrode will be co-incident with a The e inner end-of theskirt of the insulating plug so that the inner open end of thecompressed fluid chamber within said skirt is arranged opposite andadjacent to said spherlcal electrode and opens into the chamber withinthe inner end of the shell.

distributed around the is, without angular orsharp edges, points,

projections or roughness. When the opposing electrode surfaces are thussmooth and curved the sparks can jump in either direction across thespark gap, and the electrical energy is stored or held back to attainthe high potential necessary to produce an exceedingly rich electricaldischarge of high caloric value and efficiency for ignition purposes. Ifind that peculiarly a vantageous results and increased efliciency areattained in the operation of internal combustion engines by theemployment of spark plugs or ignition devices embodying electricalcondensers composed of the opposing electrodes and the interveningignitlng spark gaps. With such a condenser, a spark gap of the desiredwidth can be attained and even with an excess of oil and carbon on thecondenser electrodes the exceedingly rich sparks are given off and theintensity thereof seems to be increased by the presence and combustionof the oil and carbon. To form the electrical condenser, the o posingsurfaces of the electrodes are roundgd or curved, and to remove all finepoints or roughness which might permit current leakage and thus preventthe condenser action, said'surfaces are burnished or olished as byapplication of suitable ely divided abras1ve and polishing material.

In the example shown, the two chamhas formed in the shell around andwithin the depending skirt 21, have annular outlets bustion thereof bythe exceedingly rich sparks produced by the condenser.

It is evident that various modifications, variations, and changes mightbe resorted to, that elements or features might be added or otherelements or features omitted, without departing from the spirit andscope of my invention and hence I do not wish to limit myself to theexact constructions shown.

the

nular rounded surface electrode, and an op-.

posing spherical electrode arranged therein and separated therefrom byan annular spark gap, said electrodes having smooth burnished surfaces.

3. An igniting device comprising an annular electrode rounded in icrosssection, and an opposing spherical electrode arranged therein and spacedtherefrom to form an annular spark gap.

4. A spark plug having its shell formed at its open end with an internalsmooth annular bead rounded in cross section and constituting anelectrode, and an opposin smooth rounded surface electrode arrangetherein and spaced therefrom to form an annular spark gap.

5. A spark plug havin an annular electrode, and a spherical e ectrodearranged ner open end and forming an electrode, an insulating plugarranged longitudinally within said shell and having a skirt formingchambers within the shell for the compressed charge, and a stem withinsaid in-- sulating plug and provided with a spherical electrode arrangedadjacent to the edge of said skirt and within said annular electrode andspaced therefrom by an annular spark gap forming the opening to saidchambers,

substantially as described.

7 A spark plug comprising a shell having an internal annular electrode,an insulating plug arranged longitudinally within said shell and havinga longitudinal skirt forming compressed charge chambers within the shelland around the skirt and within the skirt, and a conducting stemarranged longitudinally of said insulating plug and provided with acentral rounded electrode within said annular electrode and spacedtherefrom to form an annular spark gap, said central electrode formingannular outlets from said chambers, substantially. as described.

In testimony whereof I afiix my signature, in presence of two witnesses.

LOUIS BOND CHERRY Witnesses:

CoRA GERBERICH, RAY WEBB.

